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Iron ore tailings (IOT) are industrial solid wastes that pose environmental threats. This study prepared IOT-biochar composite materials as multifunctional soil conditioners through an in-situ growth method. Biochar served as a carrier to improve the dispersity and reactivity of IOT in soil. The IOT-biochar composite (FeOT-BC) showed balanced impacts on soil properties, increasing pH, organic matter and available nutrients compared to IOT alone. This was due to the buffering effects of biochar. In pot experiments, FeOT-BC significantly promoted rice plant growth compared to IOT alone. The improvements were attributed to the improved soil fertility and increased microbial activities induced by biochar. The results suggest that integrating IOT with biochar can mitigate the negative effects of tailings and convert them into a value-added product. The biochar component can optimize the performance of IOT by moderating soil acidification, enhancing nutrient release from iron minerals, and stimulating microbial activities. The IOT-biochar composite materials integrate the functionalities of both components for optimized soil conditioning effects, providing a promising strategy for comprehensive tailings utilization. [ABSTRACT FROM AUTHOR]

The presence of antibiotics in wastewater has become a significant concern due to their potential environmental impact and contribution to antibiotic resistance. In this study, we investigated the degradation of tetracycline, a commonly used antibiotic, in wastewater using a system based on zero-valent nano iron assisted micro-nano bubbles (MB/nZVI). The synthesized nZVI-BC composite, consisting of nano zero-valent iron particles loaded onto phosphoric acid-activated biochar, served as an efficient adsorbent for tetracycline removal. Our findings revealed that the combination of MBs and nZVI significantly enhanced the degradation efficiency of tetracycline. The MB/nZVI system exhibited the highest removal rate of 82.81% after a 2 h reaction, surpassing the performance of MB alone, nZVI-BC alone, and conventional bubble (CB)/nZVI-BC systems. Furthermore, the MB/nZVI system showed superior degradation performance at a dosage of 25 g/L and an MB flow rate of 30 mL/min. The pH condition had no significant effect on tetracycline degradation in the MB/nZVI system. Our results demonstrate that the use of MB/nZVI has the potential to be a sustainable and efficient approach for the remediation of tetracycline-contaminated wastewater. [ABSTRACT FROM AUTHOR]

Smart agro-practices over the years have revolutionized the agriculture sector and promoted the concept of sustainable agriculture. One such practice is use of agro-waste biochar in agricultural, environmental, and climatic operations. The viability of using a biochar-based nanocomposite as a support fertilizer for the gradual release of nitrogen, potassium, and phosphorus in various media is examined in this study. The banana peel biochar (BPBC) and its nanocomposite (BNF) were prepared using a simple yet comprehensive chemical process. Synthesized materials were evaluated using FT-IR and SEM/EDX. Physical attributes as well as fertilizer basic characteristics were determined and prepared nanocomposite demonstrated noticeably better water absorbance ratio (68%), equilibrium water content (78.97%), and swelling ratio (3.64 g g−1) than biochar, which is advantageous for preserving soil water levels. The salt index values (0.087mmhos/cc) of the created nanocomposite performed better when compared to the conventional fertilizers due to their safer application. Long-term availability of all doped minerals to the plants, during experimental cycle, was revealed by slow-release nutrient studies in water and soil, which is ideal for promoting germination and growth. The findings of this research revealed that prepared BNF showed improved germination parameters i.e., time for 50% germination (3.4, 3.3, 4.4 days), germination index (3.1, 3.5, 2.4), final germination percentage (91.7, 100, 83.3%), mean germination time (4.0, 3.9, 4.9 days), for cucumber, broccoli and okra, respectively. In addition to that the prepared BNF facilitated enhanced shoot and root length in all the three vegetables as compared to conventional fertilizers. The dose optimization studies depicted that best results of germination as well as plant growth parameters are facilitated by BNF (37.5 kg/ha) owing to enhancement in soil quality by supplying additional organic matter in addition to provision of nutrients on slow-release. [ABSTRACT FROM AUTHOR]

In this work, the adsorption capacity of the biochar obtained from Pinus patula biomass micro-gasification was studied using malachite green (MG) as the probe pollutant. For this purpose, the biomass type (wood pellets and chips) was selected to produce two kinds of biochar (BC). Afterwards, the effects of the adsorbent dose (6, 9 and 12 g/L), the solution pH (4, 7 and 10) and the BC particle size distribution (150–300, 300–450 and 450–600 μ m) for the maximization of the MG retention by the selected BC were evaluated using a faced-centered central composite design, as response surface methodology. The results indicated that the BC derived from wood chips (BWC) exhibited a higher MG dye adsorption capacity than the BC obtained from the wood pellets (BWP) gasification under the same operating conditions after having reached the equilibrium. A second-order regression model was built for describing the MG adsorption behaviour by BWC under the considered experimental domain. The model, which was validated, resulted to be statistically significant and suitable to represent the MG adsorption by the studied BC with a p-value of 0.00 and a correlation coefficient (R2) of 95.59%. Additionally, a three-dimensional response surface graph and a contour plot were utilized to analyze the interaction effects between the factors influencing the adsorption system and to discern the optimal operating conditions for the use of BWC. The maximal MG dye retention (99.70%) was found to be at an adsorbent dose, pH solution and a particle size distribution of 9.80 g/L, 10 and from 150 to 300 μ m, respectively. Therefore, the BWC tested can be utilized for the treatment of water polluted with dyes, contributing to the establishment of a circular economy. [ABSTRACT FROM AUTHOR]

Global warming have become a stress condition due to the generation of greenhouse gases from the burning of fossil fuels and deforestation with the industrial revolution. Climate change induces biotic and abiotic stress conditions which badly disturb the yield of crops with leading to the biochemical and physiological damages to plants. Therefore; this study investigated the capability of Morus alba L. wood biochar and plant growth promoting rhizobacteria PG1 (Pseudomonas sp.) and PG2 (Staphylococcus haemolyticus) to alleviate the drought condition in Brassica napus L. plant. In the current research work, the combined application of plant growth promoting rhizobacteria (PGPRs) and biochar triggered an enhancement in physicochemical properties of soil including %field capacity, water use efficiency, germination parameters including Timson germination index, final emergence percentage, mean germination time, final germination percentage, germination energy, mean emergence time, germination rate index and vegetative parameters including seed vigor indexes (SVI-I & SVI-II) and plant height stress index. Inoculation and co-inoculation of PGPRs and biochar positively promote the canola plant growth even under induce drought stress condition. A positive increase in B. napus biomass including leaf area, plant height and root growth and its dry and fresh mass at p < 0.05 level, which support the effectiveness of this approach. Results also showed that Staphylococcus haemolyticus individually and in combination with biochar even under stress condition promote canola plant growth more than Pseudomonas sp. We concluded that under stressors, co-application of PGPRs and biochar could be an operative approach for enhancing plant productivity and its development. [ABSTRACT FROM AUTHOR]

Recently, scientists have shown interest in utilizing biochar made from natural sources to enhance various photovoltaic technologies. In this study, Zinc-Bis-8-hydroxyquinoline (Zn-Hq2) was mixed with 10 % biochar obtained from red sea microalgae (Chlorophyta) using a microwave combustion process. This mixture was then used as a novel photoactive layer in a solar cell. The structural properties of Zn-Hq2@BC were analyzed by XRD, FTIR, HRTEM, and SEM. The analysis showed that Zn-Hq2@BC had evenly distributed nano-rods within the BC nanopores network, with widths ranging from 26.94 to 30.90 nm and lengths ranging from 136.43 to 192.38 nm. When measuring dark current density-voltage, it was found that Zn-Hq2@BC/n-Si showed better-rectifying characteristics compared to pristine Zn-Hq2/n-Si, with a higher rectification ratio. The results also showed that the current density and voltage at the maximum power point increased to 5.63 mA/cm2 and 0.45 V, respectively, due to the activation of the biochar. When exposed to light, the addition of approximately 10 % biochar resulted in a 15 % increase in fill factor and a 92 % increase in power conversion efficiency. This is because biochar helps introduce extra charge carriers into the material, thus improving charge transport and reducing recombination losses. These findings reveal the positive effects of microalgae-derived biochar and indicate potential applications of Zn-Hq2 in solar cells. [ABSTRACT FROM AUTHOR]

A novel and efficient process for the removal of Ce(IV) from aqueous solutions was sought, and a new magnetic porous biochar (PBC/ZF) was synthesized by loading ZnFe 2 O 4 (ZF) onto porous biochar (PBC) using a one-step hydrothermal method. The SEM observation of the external features showed that the cubic spinel structured ZnFe 2 O 4 (ZF) particles were loaded onto the porous biochar (PBC) surface. This resulted in a composite with superb paramagnetic properties as well as higher adsorption properties. In addition, the microstructure was characterized by FTIR, which demonstrated that the target material was supplied with a large amount of carboxyl groups (-COOH) by citric acid during the synthesis process. The BET showed that the target material had a higher specific surface area than ZnFe 2 O 4 with PBC, confirming the successful preparation of the target material after activation of the biomass using ZnCl 2 immersion as well. The effect of different factors on the adsorption effect was investigated experimentally. The results showed that PBC/ZF had a good adsorption effect on Ce(IV) with a short adsorption equilibrium time and a maximum adsorption capacity of 228.9 mg/g at room temperature with lower acidity (pH = 2.5). The adsorption kinetics and isotherm analysis showed that the Ce(IV) adsorption process fitted well with the quasi-secondary kinetic model and Langmuir model. It indicates that the process is a single molecular layer adsorption process. It was demonstrated that PBC/ZF also has high removal rate for high concentration Ce(IV) solution, and it is easy for solid-liquid separation under the action of applied magnetic field after adsorption. It provides a new treatment method and theoretical support for the adsorption treatment technology of Ce (IV) wastewater. [ABSTRACT FROM AUTHOR]

Biochar was proposed as a novel carbon source for synthesizing Ti 3 SiC 2 powder with high purity by a simple pressureless sintering at 1673 K, and Ti 3 SiC 2 grains exhibited the typical nanolayered structure. The oxidation behavior of Ti 3 SiC 2 powder showed the parabolic law during isothermal oxidation from 1273 K to 1473 K. Dense and continuous oxidation layer consisting of mixed TiO 2 and SiO 2 was formed rapidly on the surface of Ti 3 SiC 2 particles as a diffusion barrier, which effectively retarded the inward diffusion of oxygen, conferring good oxidation resistance of the powder. [ABSTRACT FROM AUTHOR]

Phosphorus, P deficiency by adsorption and fixation of applied P is a critical problem in the tropical soils coupled with wastage of agricultural land and potential nutrients from crop residues' decomposition necessitates conservancy and sustainable management. Maize stover biochar (mB) and sawmill waste biochar (sB) pyrolysed for 60-minute at 460 °C using Top-Lit Up Draft (TLUD) carbonizer were characterized by morphological, elemental and proximate properties analysed by Scanning Electron Microscope (SEM), CHNS Elemental Analyser and appropriate methods, respectively. Phosphorus (P) adsorption potential of the biochars in charnockite-originated soils were evaluated using adsorption isotherms after adding biochars at 0, 5, 10 and 20% (w/w) with concentrations of 0, 15, 30, 60, 90, 120, 150 mg P/L. SEM showed macropores (>50 nm) embedded biochars, with higher elemental C and H in sB while mB contained higher N, S, O, available P and pH. P-adsorption decreased inconsistently with increasing biochar rates resulting in P-desorption. Low Langmuir adsorption maximum (Qm) were recorded (−0.0350 to 0.1250 mg kg−1) mostly with negative separation factors (R L) and the adsorption process were favourable for mB amended soils having Freundlich heterogeneity factor (n F) of 4.476–9.634 but not for sB amended soils (n F = 0.638–2.812). Biochar production conserved nutrient loss and potentially reduced soil P fixation. [ABSTRACT FROM AUTHOR]

Under the circumstances of serious environmental challenges and energy crises, it is of utmost importance to produce fuels and chemicals from renewable biomass and organic wastes. Biochar as a bioproduct from thermochemical conversion of biomass has attracted exponential research interest in recent years due to the abundance of its precursor (biomass resources) and its adaptability in different chemical reaction systems. Undoubtedly, it is essential to attain an in-depth understanding of the physiochemical properties and functionalization of biochar catalysts to further improve their catalytic activity, selectivity and stability in the reactions. However, until now, only a few reports are accessible on the use of biochar as a catalytic support material and/or a standalone catalyst in thermochemical biomass conversion to produce high-quality biofuels. Thus, the key objective of this review article is to summarize and discuss the latest progress in biochar production, modification, activation and functionalization by understanding its physical chemistry, composition and application in catalytic processes. This review article provides insights into the thermochemical and hydrothermal production of biochar as well as the engineering and process optimization aspects for value-added biofuel production and decarbonization. [Display omitted] • Effects of biomass composition and process conditions on biochar are reviewed. • Systematic discussion on biochar functionality as bio-based catalyst support is made. • Insights into the modification of biochar targeting optimal performance are shown. • Comparative analysis of biochar-based catalytic pyrolysis, gasification and liquefaction. • The significance of activation of biochar for enhanced functionality is justified. [ABSTRACT FROM AUTHOR]

Biochar materials have wide applications in soil improvement/remediation, water pollution control, gas storage, and heterogeneous catalysis, while usually suffering from low surface areas and harsh preparation conditions. In this study, a green, environmentally friendly, and low-cost biochar catalyst (PAP-MEPP-C) was prepared by thermochemical treatment of lignin-derived monomers at a low temperature (80 °C), and further developed for high-efficiency production of biodiesel from non-edible Jatropha oil (J O). The characterization results showed that the structure of the PAP-MEPP-C biochar catalyst was layered and 3D structure, and its acidity could be controlled by changing the monomeric composition. The reaction conditions of preparing biodiesel catalyzed by PAP-MEPP-C were optimized by the response surface method, and the obtained maximum biodiesel yield was 97.2%. The kinetics of the (trans)esterification reaction over the developed biochar catalyst PAP-MEPP-C was studied, and its superior catalytic performance to other tested acid catalysts could be supported by a relatively lower activation energy (36 kJ mol−1). In addition, the biochar catalyst was highly stable and could be recycled four times with more than 90% biodiesel yield. [Display omitted] • A novel 3D layered biochar with tunable acidity was prepared by treatment at 80 °C. • Response surface method optimized the catalytic conditions of prepared biochar. • The yield of biodiesel from Jatropha oil over the biochar catalyst was up to 97.2%. • The biochar catalyst had good reusability with biodiesel yield of > 90% after 4 cycles. • The biochar catalyst is active for producing biodiesel from oils with high acid value. [ABSTRACT FROM AUTHOR]

This study evaluates the environmental impacts associated with the conversion of garden organic waste into value-added products, namely compost or biochar, employing various processes. Three distinct scenarios are considered: composting garden organic waste followed by screening of oversized materials (CBP), pyrolysis of oversized screenings of compost into biochar AP(I), and in-situ conversion of garden organics into biochar AP(II). A comprehensive Life Cycle Assessment (LCA) was conducted using OpenLCA software and life cycle impact assessment was conducted using Recipe 2016 midpoint methodology. The environmental ramifications of each scenario were assessed, optimising transport distances in AP(II) to achieve a functional unit of one tonne of biochar produced within a cradle-to-gate system boundary. For the first time, this study offers a holistic exploration of the benefits of soil biochar application, extending its scope to climate change mitigation, incorporating the optimisation of transport distance and its influence when scaling up the technology. The results revealed that global warming was increased from 125 kgCO 2 eq during composting of garden waste to 232 kgCO 2 eq where oversized screenings of compost is converted to biochar at an off-site facility. However, direct conversion of the oversized organic waste to biochar, without composting, showed reduced global warming impact of 56 kgCO 2 eq, and is thus the most favourable scenario to limit climate impacts of this fraction of organic garden waste. However, among 18 environmental impact indicators studied, eight indicators were either not influenced or did not significantly increase by transport distance to an off-site pyrolysis facility, while the magnitude of 10 impact indicators increased with transport distance. The insights and methodologies presented in this study hold global relevance, based on an actual case study in regional Australia, offering valuable recommendations for sustainable waste management practices and establishing biochar as a carbon-neutral or carbon-negative solution. The findings contribute to existing waste management knowledge and provide guidance for accessible carbon dioxide removal and soil carbon sequestration technologies. [Display omitted] • A comprehensive LCA for valorisation of garden organics was conducted. • Direct conversion of garden organics to biochar showed least potential environmental impacts. • Biochar provides opportunities for avoided, reduced, and removed carbon from atmosphere. • Maximum transport distance has been identified for individual impact categories. [ABSTRACT FROM AUTHOR]

In this study, seven types of biomass (coffee husk, macadamia husk, peanut husk, rice husk, rice straw, tobacco straw, and cotton straw) were carbonized at temperatures ranging from 300 °C to 1000 °C. This study explored the potential of these biomass samples as carbon reducing agents for industrial silicon and compared them with charcoal in terms of their proximate analysis, electrical resistivity, and apparent activation energy of the reaction. The results indicated that as the pyrolysis temperature increased, the oxygen content and aliphatic functional groups in biochar gradually decreased, as did the volatiles content, while the proportions of fixed carbon and ash increased. The resistivity decreased upon the removal of volatiles and an increase in the degree of graphitization. At 600 °C, the fixed carbon content of all biochar exceeded 65%, and the fixed carbon content of macadamia husk biochar reached 91.32%, which was higher than that of charcoal (81.44%), the maximum specific surface area was 335.706 m2/g, which was much higher than that of charcoal (5.705 m2/g). Thermogravimetric analysis and kinetic analysis indicated that coffee husk had better reactivity than charcoal. The gasification reactivity of coffee husk was R = 3.1949%/min °C, which was higher than that of charcoal (0.7930 %/min °C). The apparent activation energy during the coking reaction stage was 51.86 kJ/mol, which was lower than that of charcoal (98.9 kJ/mol). Overall, biochar had a suitable fixed carbon and electrical resistivity at 600 °C and can be used as a carbon reducing agent for industrial silicon, among them, macadamia husk with high fixed carbon and coffee husk with high reactivity have greater application potential. [Display omitted] • The first proposal to use biomass as a reducing agent for industrial silicon • Coffee husk and macadamia husk have better performance than charcoal. • The mechanism of biomass carbonization was analyzed through kinetic analysis. • The electrical resistivity of biochar decreases with increasing temperature. [ABSTRACT FROM AUTHOR]

This study presents novel composites of biochar (BC) derived from spinach stalks and zinc oxide (ZnO) synthesized from water hyacinth to be used for the first time in a hybrid system for activating persulfate (PS) with photocatalysis for the degradation of bromothymol blue (BTB) dye. The BC/ZnO composites were characterized using innovative techniques. BC/ZnO (2:1) showed the highest photocatalytic performance and BC/ZnO (2:1)@(PS + light) system attained BTB degradation efficiency of 89.47% within 120 min. The optimum operating parameters were determined as an initial BTB concentration of 17.1 mg/L, a catalyst dosage of 0.7 g/L, and a persulfate initial concentration of 8.878 mM, achieving a BTB removal efficiency of 99.34%. The catalyst showed excellent stability over five consecutive runs. Sulfate radicals were the predominant radicals involved in the degradation of BTB. BC/ZnO (2:1)@(PS + light) system could degrade 88.52%, 84.64%, 81.5%, and 77.53% of methylene blue, methyl red, methyl orange, and Congo red, respectively. Further, the BC/ZnO (2:1)@(PS + light) system effectively activated PS to eliminate 97.49% of BTB and 85.12% of dissolved organic carbon in real industrial effluents from the textile industry. The proposed degradation system has the potential to efficiently purify industrial effluents which facilitates the large-scale application of this technique. [Display omitted] • Hybrid photocatalysis/PS activation system could efficiently degrade BTB dye. • 99.34% degradation efficiency of BTB was achieved under the optimal condition. • Sulfate radicals were the main radicals involved in the degradation system. • The constituents of water matrices inhibited the accelerated degradation rates. • The proposed system could degrade 97.49% BTB and 85.12% DOC from real wastewater. [ABSTRACT FROM AUTHOR]

This study investigates the potential of spent coffee ground biochar (SCGB) as a sustainable and cost-effective adsorbent for the removal of methylene blue (MB), a hazardous dye commonly used in the textile and printing industries. A response surface methodology (RSM) approach with central composite design (CCD) was employed to systematically investigate the effects of key process parameters, including adsorbent dosage, solution pH, contact time and temperature, on MB removal efficiency. The analysis revealed that adsorbent dosage and temperature as critical factors influencing MB removal, with a linear model providing a strong correlation. Optimal conditions for MB removal were determined to be 0.99 g of SCGB, 30 min of contact time, 30 °C temperature, and a solution pH of 7. Under these conditions, MB removal reached 99.99%, with a desirability of 1.000. The experimental results closely matched the predicted values, differing by only 0.02%, thus validating the accuracy of the model. Kinetic studies indicated a rapid adsorption process, well-described by both pseudo-first and pseudo-second order models. Isotherm analysis confirmed the applicability of the Freundlich model, suggesting favorable adsorption with increasing MB concentration. The high adsorption capacity of SCGB is attributed to its carbonaceous and porous structure, highlighting its potential as an effective adsorbent for dye removal in wastewater treatment applications. [Display omitted] • SCGB removes 99.99% of MB under optimal conditions. • Adsorbent dosage and temperature are the most important factors for MB removal. • DOE accurately predicted experimental parameter values. • Rapid adsorption and equilibrium were reached in 2 h. [ABSTRACT FROM AUTHOR]

Food-waste biochar holds significant potential as a bio-solid fuel for achieving carbon neutrality; however, its high content of sodium (Na), potassium (K), calcium (Ca), chlorine (Cl), and nitrogen, inhibits its potential use. This study explored the effects of post-treatment with ascorbic, acetic, citric, and iminodiacetic acids on the properties of food-waste biochar and volatile ionic substances to establish a foundation for assessing both the environmental impact and practical use of food waste. Post-treatment with organic acids achieved 92% Cl-removal efficiency and induced deformation of the functional groups of food-waste biochar surfaces, leading to the re-adsorption of alkali and alkaline earth metals. This re-adsorption of alkali metal ions showed a distinct correlation with NO x mitigation. The amount of re-adsorbed Na and K varied based on the types of organic acids, resulting in different NO x emission reduction effects. Iminodiacetic acid was particularly effective in alleviating Ca and PO 4 volatilization, whereas citric acid exhibited the highest Ca elution performance, and the Ca-contained leachate is a potential source of CO 2 storage through indirect mineral carbonation. Acetic acid is the most feasible alternative, considering both economic and environmental aspects. The findings suggest that the post-treatment of food-waste biochar effectively mitigates air pollutants during combustion and is beneficial for sustainable biosolid fuel production and bio-waste management. [Display omitted] • Post-treatment with organic acids efficiently removes 92% of Cl from food waste biochar. • Elute variation with the type of organic acid causes different energy yields. • Re-adsorbed alkali metals on the biochar surface significantly correlated with NOx reduction (R2 = 0.9773). • Iminodiacetic acid particularly reduces Ca and PO 4 volatilization. • Acetic acid is cost-feasible for improving biochar quality as a bio-solid fuel. [ABSTRACT FROM AUTHOR]

Using biochar for dye wastewater treatment is attracting interest due to its excellent adsorption properties and low costs. In this work, a novel biochar derived from oxytetracycline fermentation residue (functionalized OFR biochar, FOBC) was investigated as a efficient adsorbent for typical dyes removal. At 25 °C, the maximum adsorption capacity calculated by Langmuir model of FOBC-3-600 for methylene blue (MB), malachite green (MG), and methyl orange (MO) reached 643.97, 617.89, and 521.03 mg/g, respectively. The kinetics and isotherm model fitting showed that the chemisorption and physisorption both occurred during the adsorption process. Dyes were efficiently adsorbed through pore filling, electrostatic attraction, π-π interactions, and surface complexation. And the cycling experiment and environmental risk assessment indicated that the FOBC-3-600 had excellent recyclability and utilization safety. Overall, this study provides a practical method to simultaneously treat the dyeing wastewater and utilize the antibiotic fermentation residue. [Display omitted] • Oxytetracycline fermentation residue was converted into N-doped porous biochar. • FOBC-3-600 had high specific space area (1269 m2/g) and nitrogen content (5.85 wt%). • FOBC-3-600 showed a superior adsorption capacity for three typical dyes. • Chemisorption played a major role in the adsorption process. • FOBC-3-600 had excellent recyclability and utilization safety. [ABSTRACT FROM AUTHOR]

Microalgae can be collected in large quantities and hold significant potential for environmental remediation, offering a cost-effective solution. This study explores the use of Spirulina platensis (SP) as feedstock for biochar production. SP contains abundant nitrogen-rich components, such as proteins, which can serve as nitrogen sources. We prepared SP-derived biochar through pyrolysis for the adsorption of Pb and Zn from aqueous solutions and used it as an amending agent to remediate heavy metal-contaminated agricultural soil. Pyrolysis of proteins in SP introduces nitrogen-functional groups, resulting in nitrogen-doped biochar. We investigated the surface chemical behavior of thermally treated SP using X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. Surface analysis revealed the presence of pyridine-N and pyrrole-N from protein pyrolysis products. The study also demonstrated that these functional groups affect interactions with heavy metals. Batch experiments examined the effects of pH and initial concentration on the adsorption of Pb and Zn using SP400 and SP600. Both types of biochar showed satisfactory performance in adsorbing Pb and Zn. The effect of SP400 and SP600 on the removal of Pb and Zn through the physicochemical properties and surface functional groups was investigated. Analysis of SP400 and SP600 highlighted that electrostatic interactions, cation exchange, complexation, and mineral precipitation contributed to Pb and Zn adsorption. The study concludes that SP-derived biochar, particularly SP600, is effective for immobilizing Pb and Zn in contaminated agricultural soil, with SP600 showing superior performance. [Display omitted] • Spirulina platensis (SP) can be effectively converted into biochar, which has proven successful for removing Pb and Zn. • SP-derived biochar exhibits strong alkaline properties and diverse functional groups, leading to a high adsorption capacity for Pb and Zn. • SP derived biochar effectiveness was studied for treating heavy metal-contaminated soil. [ABSTRACT FROM AUTHOR]

Constructed wetlands (CWs) can play a crucial role in treating wastewater, and in the context of this study, the distillation byproduct of the whisky industry known as 'spent lees'. Here, we assess several different CW substrates (pea gravel, LECA and Alfagrog), with and without the addition of 20% biochar, in mesocosms set up to treat spent lees. Among the substrates tested, LECA + biochar and gravel + biochar showed promising results, with greater dissolved copper (dissCu) reduction, chemical oxygen demand (COD) removal, organic carbon (OC) reduction, and pH modulation. These findings indicate a potentially beneficial role for biochar in enhancing treatment efficacy, particularly in facilitating dissCu remediation and the removal of organic pollutants. In terms of microbial diversity, mesocosms including biochar generally had reduced bacterial alpha diversity, suggesting that 'fresh' (uncolonized) biochar may negatively affect microbial diversity in wetland ecosystems in the short term. After continuously supplying spent lees to mesocosms for 2-months, microbial diversity in each mesocosm dropped substantially, and moderate levels of bacterial community differentiation and high levels of fungal community differentiation were detected among mesocosms. The bacterial and fungal communities were also found to differ between the substrate and outlet water samples. Among the bacterial classes present in the mesocosms that may play a crucial role in water treatment performance, Gammaproteobacteria, Bacteroidia and Alphaproteobacteria should be further investigated. In terms of fungal classes, the role of Sordariomycetes should be explored in greater depth. [Display omitted] • CW mesocosms treat whisky distillation byproduct 'spent lees' effectively. • LECA + biochar and gravel + biochar mesocosms show high pollutant removal. • Fresh biochar enhances treatment but reduces microbial diversity short-term. • Two-month treatment drops microbial diversity, shows bacterial/fungal differentiation. • Gammaproteobacteria, Bacteroidia and Sordariomycetes are suggested to be investigated. [ABSTRACT FROM AUTHOR]

Military activities and the production or disposal of ammunition often lead to soil contamination with energetic compounds (ECs) such as dinitrotoluene, trinitrotoluene, and hexogen, posing significant threats to human health and the ecosystem. Biochar has emerged as a cost-effective and widely available solution for remediating contaminated sites characterized by its capacity for pollutant removal through adsorption and conversion process, along with minimal secondary pollution. This paper provides a comprehensive review of relevant literature on biochar's efficacy in eliminating ECs, including an analysis of the underlying mechanisms. The discussion addresses challenges and opportunities associated with biochar application in ECs remediation, offering insights for future research directions. In summary, the use of biochar for ECs removal presents a promising and eco-friendly approach, facilitating the remediation of contaminated sites while promoting soil function and ecosystem recovery. [Display omitted] • Reviewed the functions of biochar in the removal of ECs. • Biochar adsorbed ECs via π−π electron donor-acceptor and hydrophobic interactions. • Biochar facilitated ECs conversion through conductive planes and redox components. • Biochar offers both remediation and ecological advantages. [ABSTRACT FROM AUTHOR]

[Display omitted] • Plants respond to drought stress via stomatal regulation and stress signaling. • Using Plant growth-promoting bacteria helps plants alleviate drought stress. • Arbuscular mycorrhizal fungi and biochar enhance water and nutrient uptake. • Genetic approaches help plants to resist drought stress. • The use of phytohormones helps plants to regulate response mechanisms. [ABSTRACT FROM AUTHOR]

Biochar is considered a promising biosorbent for harmful organic pollutants in aqueous media. However, only a limited number of biochars derived from industrial sludges have been utilized due to their problematic high ash content and heavy metal leaching. In this study, a highly effective biochar was prepared as a superabsorbent for ciprofloxacin (CIP) from chemical manufacturing plant sludge via K 2 CO 3 -activated pyrolysis, and its CIP removal behavior was evaluated. Unlike sewage sludge, chemical manufacturing plant sludge contains low SiO 2 , resulting in an ultra-pure carbon (95.4%) based biochar with almost negligible ash content. As the pyrolysis temperature increased from 400 to 800 °C, the ordered graphitic carbon structure transformed into an amorphous carbon phase, and most oxygen-containing groups disappeared. However, the pore size significantly decreased to ∼4.5 nm due to the corrosive carbon volatilization caused by K 2 CO 3 , resulting in an extremely large surface area of 2331.8 m2/g. Based on its large surface area and porous carbon structure, the activated biochar at 800 °C (CAB-800) exhibited an outstanding CIP adsorption capacity of 555.56 mg/g. The CIP adsorption isotherm, kinetic, and thermodynamic studies were systematically investigated. The CIP adsorption on CAB-800 was mainly attributed to π-π interactions and hydrogen bond formation, with electrostatic interactions partially contributing to the adsorption reaction. From pH 2 to 12, CAB-800 showed an excellent CIP adsorption capacity of over 316.7 mg/g, with adsorption favored under acidic conditions. Except for HCO 3 − and CO 3 2−, the presence of anions and humic acids did not significantly affect CIP adsorption capacity. These results demonstrate that biochar produced from chemical manufacturing industry sludge via K 2 CO 3 activation is a highly feasible material for the removal of CIP from aqueous media. [Display omitted] • A superabsorbent for the removal of ciprofloxacin (CIP) was prepared from chemical plant sludge. • The chemical plant sludge has a low ash content, resulting in nearly pure C-based biochar. • The biochar exhibits an outstanding CIP uptake of 555.6 mg/g due to its large surface area. • Hydrogen bond and π-π interactions are the primary mechanisms for CIP adsorption. • Electrostatic interactions between CIP and biochar also contribute partially to CIP adsorption. [ABSTRACT FROM AUTHOR]

Concurrent heavy metals remediation in natural environments poses significant challenges due to factors like metal speciation and interactions with soil moisture. This review focuses on strategies for immobilizing both anionic and cationic metals simultaneously in soil-crop systems. Key approaches include water management, biochar utilization, stabilizing agents, nanotechnology, fertilization, and bioremediation. Sprinkler or intermittent irrigation combined with soil amendments/biochar effectively immobilizes As/Cd/Pb simultaneously. This immobilization occurs through continuous adsorption-desorption, oxidation-reduction, and precipitation mechanisms influenced by soil pH, redox reactions, and Fe-oxides. Biochar from sources like wine lees, sewage sludge, spent coffee, and Fe-nanoparticles can immobilize As/Cd/Pb/Cr/Co/Cu/Zn together via precipitation. In addition, biochar from rice, wheat, corn straw, rice husk, sawdust, and wood chips, modified with chemicals or nanoparticles, simultaneously immobilizes As and Cd, containing higher Fe 3 O 4 , Fe-oxide, and OH groups. Ligand exchange immobilizes As, while ion exchange immobilizes Cd. Furthermore, combining biochar especially with iron, hydroxyapatite, magnetite, goethite, silicon, graphene, alginate, compost, and microbes—can achieve simultaneous immobilization. Other effective amendments are selenium fertilizer, Ge-nanocomposites, Fe–Si materials, ash, hormone, and sterilization. Notably, combining nano-biochar with microbes and/or fertilizers with Fe-containing higher adsorption sites, metal-binding cores, and maintaining a neutral pH could stimulate simultaneous immobilization. The amendments have a positive impact on soil physio-chemical improvement and crop development. Crops enhance production of growth metabolites, hormones, and xylem tissue thickening, forming a protective barrier by root Fe-plaque containing higher Fe-oxide, restricting upward metal movement. Therefore, a holistic immobilization mechanism reduces plant oxidative damage, improves soil and crop quality, and reduces food contamination. [Display omitted] • Simultaneous metals immobilization is challenging for various factors. • Soil pH and redox reaction greatly influence the immobilization. • Fertilization with sprinkler or intermittent irrigation can reduce both As and Cd. • Nano-biochar with microbes can initiate simultaneous immobilization. • The pathways of anionic metalloids and cationic metals are discussed. [ABSTRACT FROM AUTHOR]

This work aims to assess the surface coupling of molecularly imprinted polymers (MIP) on carbon adsorbents produced from spent brewery grain, namely biochar (BC) and activated carbon (AC), as a strategy to improve selectivity and the adsorptive removal of the antibiotic sulfamethoxazole (SMX) from water. BC and AC were produced by microwave-assisted pyrolysis, and MIP was obtained by fast bulk polymerization. Two different methodologies were used for the molecular imprinting of BC and AC, the resulting materials being tested for SMX adsorption. Then, after selecting the most favourable molecular imprinting methodology, different mass ratios of MIP:BC or MIP:AC were used to produce and evaluate eight different materials. Molecular imprinting was shown to significantly improve the performance of BC for the target application, and one of the produced composites (MIP1-BC-s(1:3)) was selected for further kinetic and equilibrium studies and comparison with individual MIP and BC. The kinetic behaviour was properly described by both the pseudo-first and pseudo-second order models. Regarding equilibrium isotherms, they fitted the Freundlich and Langmuir models, with MIP1-BC-s(1:3) reaching a maximum adsorption capacity (q m) of 25 ± 1 μmol g-1, 19 % higher than BC. In comparison with other seven pharmaceuticals, the adsorption of SMX onto MIP1-BC-s(1:3) was remarkably higher, as for the specific recognition of this antibiotic by the coupled MIP. The pH study evidenced that SMX removal was higher under acidic conditions. Regeneration experiments showed that MIP1-BC-s(1:3) provided good adsorption performance, which was stable during five regeneration-reutilization cycles. Overall, this study has demonstrated that coupling with MIP may be a suitable strategy to improve the adsorption properties and performance of biochar for antibiotics removal from water, increasing its suitability for practical applications. [Display omitted] • Sulfamethoxazole (SMX) can be removed from water by activated carbon and biochar (BC). • Coupling molecularly imprinted polymers (MIP) was tested to improve their performance. • A new sonication method performed better than surface imprinting for MIP coupling. • SMX adsorption capacity of MIP-BC composite was 19 % higher than that of BC. • SMX selectivity and successful reutilization over regeneration of MIP-BC were proved. [ABSTRACT FROM AUTHOR]

Global climate change is anticipated to shift the soil bacterial community structure and plant nutrient utilization. The use of biochar amendment can positively influence soil bacterial community structure, soil properties, and nutrient use efficiency of crops. However, little is known about the underlying mechanism and response of bacterial community structure to biochar amendment, and its role in nutrient enhancement in soil and plants under elevated CO 2. Herein, the effect of biochar amendment (0, 0.5, 1.5%) on soil bacterial community structure, spinach growth, physiology, and soil and plant nutrient status were investigated under two CO 2 concentrations (400 and 600 μmol mol−1). Findings showed that biochar application 1.5% (B.2.E) significantly increased the abundance of the bacterial community responsible for growth and nutrient uptake i.e. Firmicutes (42.25%) Bacteroidetes (10.46%), and Gemmatimonadetes (125.75%) as compared to respective control (CK.E) but interestingly abundance of proteobacteria decreased (9.18%) under elevated CO 2. Furthermore, the soil available N, P, and K showed a significant increase in higher biochar-amended treatments under elevated CO 2. Spinach plants exhibited a notable enhancement in growth and photosynthetic pigments when exposed to elevated CO 2 levels and biochar, as compared to ambient CO 2 conditions. However, there was variability observed in the leaf gas exchange attributes. Elevated CO 2 reduced spinach roots and leaves nutrient concentration. In contrast, the biochar amendment (B2.E) enhanced root and shoot Zinc (494.99%–155.33%), magnesium (261.15%–183.37%), manganese (80.04%–152.86%), potassium (576.24%–355.17%), calcium (261.88%–165.65%), copper (325.42%–282.53%) and iron (717.63%–177.90%) concentration by influencing plant physiology and bacterial community. These findings provide insights into the interaction between plant and bacterial community under future agroecosystems in response to the addition of biochar contributing to a deeper understanding of ecological dynamics. [Display omitted] • Biochar improved soil properties and increased phosphorus, potassium, and nitrogen availability under elevated CO 2. • Bacterial community structure and composition were greatly affected by biochar in a dose-dependent manner. • Change in bacterial community structure promoted plant growth and nutrient concentration under elevated CO 2. • Biochar amendment is a sustainable approach to boost crop productivity and quality under future climatic conditions. [ABSTRACT FROM AUTHOR]

Environmentally persistent free radicals (EPFRs) may pose a potential risk to the ecosystem and human health via oxidation stress and are considered emerging contaminants. Being stable with a lifetime of minutes or several months and abundant in transitional matrices (e.g. biochar), EPFRs continue to affect deposits (e.g. soil) and related media (plants) when the transitional matrices (e.g. biochar) are applied. The impact of EPFR on the plant uptake of chemical elements (CEs) was studied in the field conditions where, for two years, biochar and fertilisers were applied to the agricultural soil for winter triticale cultivation. EPFRs determination methods, along with the element uptake indices (bioaccumulation and biophilicity) and the method of the dynamic factors were applied. Results have shown that EPFRs have influenced the soil properties relevant to CE soil bioavailability and bioaccumulation in plants. The impact of EPFRs on CE transport in the soil–plant system was observed to influence the biogeochemical behaviour of CEs in the soil–plant system. This work provides the first findings on EPFRs-induces changes on CE bioavailability and bioaccumulation intensity, indicating the higher plant uptake risk of some potentially toxic elements (such as Cr). [Display omitted] • EPFRs favour the bioavailability of soil chemical elements. • EPFRs impact the intensity of chemical element bioaccumulation. • EPFRs affect the biogeochemical cycling of chemical elements. [ABSTRACT FROM AUTHOR]

A high-performance and affordable peanut shell-derived biochar was employed for the efficient removal of Rhodamine B (RhB) from aqueous solutions. The properties of peanut shell biochar (PSB) were investigated through Fourier transform infrared (FTIR) spectroscopy and Brunauer–Emmett–Teller surface area measurements. The FTIR analysis revealed numerous active sites and functional groups for the binding of dye molecules, while the BET surface area was determined to be 351.11 m2g-1. Four different isotherms and kinetic models were applied to determine the equilibrium adsorption of RhB, and the results indicated that the Freundlich isotherm was the most appropriate model. A maximum dye removal rate of 94.0% occurred at a pH of 3 with an adsorbent dose of 0.325 g L−1. The prepared adsorbent showed excellent sorbent behaviour and can be reused multiple times after regeneration, with the surface area decreasing from 351.11 m2g-1 to 140.13 m2g-1 after the third cycle. The negative Gibbs free energy ΔGo at all applied temperatures suggested that spontaneous adsorption occurred and RhB adsorption on the PSB was found exothermic, as evidenced by the negative value of ΔHo. The regenerated PSB can be utilized as an efficient, environmentally friendly, and cost-effective sorbent for the removal of dyes at temperatures lower than ambient temperature, providing both technical and financial advantages for sustainable environmental management. [Display omitted] • Peanut shell biochar efficiently removes the dye in aqueous solutions. • Adsorption of active sites is critical to the uptake of the dyes. • Adsorbents can be regenerated and reused to reduce the cost of treatment. • The peanut shell biochar is an economically viable sorbent option. [ABSTRACT FROM AUTHOR]

Urban residential and industrial growth development affects sustainable and healthful indoor environments. Environmental issues are a global problem. The deterioration of indoor air quality has prompted the creation of several air cleansing techniques. This review explains how carbon-based materials have influenced the development of air purification systems using photocatalysis. These carbon-based materials offer unique properties and advantages in VOC removal processes. Biochar, produced from biomass pyrolysis, provides an environmentally sustainable solution with its porous structure and carbon-rich composition. Carbon quantum dots, with their quantum confinement effects and tunable surface properties, show promise in VOC sensing and removal applications. Polymers incorporating reduced graphene oxide demonstrate enhanced adsorption capabilities owing to the synergistic effects of graphene and polymer matrices. Activated carbon fibers, characterized by their high aspect ratio and interconnected porosity, provide efficient VOC removal with rapid kinetics. With their unique electronic and structural properties, graphitic carbon nitrides offer opportunities for photocatalytic degradation of VOCs under visible light. Catalysts integrated with MXene, a two-dimensional nanomaterial, exhibit enhanced catalytic activity for VOC oxidation reactions. Using various carbon-based materials in VOC removal showcases the versatility and effectiveness of carbon-based approaches in addressing environmental challenges associated with indoor air pollution. Metal-organic-framework materials are carbon-based compounds. It examines the correlation between VOC mineralization and specific characteristics of carbon materials, including surface area, adsorption capability, surface functional groups, and optoelectronic properties. Discussions include the basics of PCO, variables influencing how well catalysts degrade, and degradation mechanisms. It explores how technology will improve in the future to advance studies on healthy and sustainable indoor air quality. [Display omitted] • Carbon foam, surface functionalization as promising material were reviewed. • VOCs (volatile organic compounds and their environmental problems. • Efficient photocatalytic remediation of VOCs pollutants on composite surface was discussed. • Comprehensive conclusion and future prospectives were also reported. [ABSTRACT FROM AUTHOR]

Nitrogen-doped biochar as Fenton-like catalysts has been widely used to remove emerging pollutants in wastewater. However, the effect of in-situ and ex-situ nitrogen doping on the Fenton-like catalytic activity of biochar is unclear. In this study, the nitrogen-doped biochar was prepared by in-situ (NBC) and ex-situ (BC–N) nitrogen doping, and the Fenton-like catalytic activity of NBC and BC-N was compared for activating hydrogen peroxide (H 2 O 2), peroxydisulfate (PDS) and peroxymonosulfate (PMS). The results showed that NBC had higher Fenton-like catalytic activity than BC-N, because the formation of carbon quantum dots (CQDs) significantly increased the adsorption capacity to H 2 O 2 , PDS and PMS. NBC could activate H 2 O 2 , PDS and PMS for degradation of sulfamethoxazole (SMX), but showed different catalytic activity and degradation mechanism. In the systems of NBC/H 2 O 2 and NBC/PDS, CQDs played a key role in the activation of H 2 O 2 and PDS, and surface-bound reactive species were mainly responsible for SMX degradation. In the system of NBC/PMS, NBC acted as both electron mediator and activator, direct electron transfer between PMS and SMX and surface-bound reactive species contributed to SMX degradation. This study provides an insight into the catalytic activity of NBC for H 2 O 2 , PDS and PMS. [Display omitted] • Effect of in-situ and ex-situ nitrogen doping on catalytic activity f was explored. • BC-N had higher surface area, but lower activity for activating H 2 O 2 , PDS and PMS. • Ex-situ nitrogen doping could produce carbon quantum dots and improve catalytic activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Free ammonia from hydrolysis of chicken manure promoted the hydrogenic fermentation. • Increased organic loading rate resulted in an increase of the hydrogen production. • Romboutsia (19.7 %) and Clostridium (16.6 %) were the dominant strains. • Biochar derived from solid digestate fraction was rich in calcium and phosphorus. • Bioaugmentation of liquid digestate removed 83.3 % of NH 4 -N and 66.2 % of COD. This study provides a sustainable approach to produce biohydrogen through the long-term hydrogenic fermentation of chicken manure (CM) in a semi-continuous stirred tank reactor (CSTR) under different organic loading rates (OLRs). To ensure the zero-waste route and sustainability , the total digestate was mechanically separated into liquid and solid fractions. The solid digestate fraction was thermally treated to produce biochar, while the liquid digestate fraction was biologically treated through bioaugmentation with a novel heterotrophic nitrification-aerobic denitrification (HD-AN (bacterial strain (Alcaligenes sp. ME-1). The results showed that the high concentration of free ammonia nitrogen (FAN) contents of CM could inhibit methanogenesis and induce hydrogen production. The ORLs of 2.5, 3.5, 4.5, and 5.5 gVS/L.d imposed to the CSTR resulted in volumetric hydrogen production (VHP) of 643.3 ± 37, 908.8 ± 64.5, 1077.8 ± 95.17, and 1383.3 ± 156.8 mL/L.d, respectively. The microbial community structures indicated the long-term adaptation of hydrogen-producing bacteria and methanogenesis inhibition. The bioaugmentation process removed 83.3 % of total ammonia and 66.2 % of the chemical oxygen demand (COD) from the liquid digestate fraction. The characteristics of the biochar derived solid digestate is suitable for land applications as fertilizer. The hybrid approach combining biohydrogenation, pyrolysis, and bioaugmentation, maximizes the utilization of chicken manure slurry while conforming to the sustainable development goals. [ABSTRACT FROM AUTHOR]

[Display omitted] • ZnCl 2 -SPI biochar was used to activate persulfate for ACP removal. • The generation and contribution of ROS depend on the persulfate-to-ACP ratio. • Electron transfer from ACP to persulfate was predominant at a low ratio. • ACP transformed to polymer via a coupling effect. This study investigated the effect of acetaminophen (ACP) removal through the ZnCl 2 -SPI/persulfate process and evaluated the production of reactive oxygen species (ROS) based on ACP concentration. ACP removal efficiency reached 96 % within 5 min, regardless of the initial concentration (40 μM and 200 μM). The change in pH had a minimal effect on the removal efficiency, and the reactivity improvement increased the removal rate at pH 4 and 10. The persulfate-to-ACP ratio significantly influenced ACP removal, with the minimum ratio required for effective ACP removal being 5. The scavenger test results showed that the effect of O 2 •− radicals prevailed when ACP concentration was 40 μM, whereas the effect of 1O 2 prevailed when ACP concentration was 200 μM. This indicates that ROS contribution depends on the persulfate-to-ACP ratio. When this ratio was high, ZnCl 2 -SPI and persulfate reacted to generate O 2 •− radicals via the radical pathway. Conversely, when this ratio was low, ACP and persulfate reacted to generate 1O 2 via the nonradical pathway. The difference in these mechanisms was analyzed through electrochemical analysis, confirming that ACP and persulfate reacted via a coupling effect. In conclusion, the ROS generated in the ZnCl 2 -SPI/persulfate process varied depending on the persulfate-to-ACP ratio, and the ROS generation path can be selectively controlled by adjusting this ratio. [ABSTRACT FROM AUTHOR]

[Display omitted] • Low lignin content in algae makes thermochemical conversion to chars cost-effective. • Slow pyrolysis and HTC are preferred methods for algal char production. • Higher porosity and more diverse functional groups boost algal sorbent properties. • Enriched ash content in algal chars leads to higher cation exchange properties. • Modification of algal char enhances biosorbent properties. Biochar and hydrochar are carbon-rich solid products of algal and terrestrial biomass obtained through various thermochemical processes, mainly hydrothermal liquefaction, pyrolysis, and hydrothermal carbonization. Both are regarded as economical, potent, and environmentally friendly adsorbents for wastewater remediation. The versatile applicability of biochar and hydrochar, which is due to their enhanced surface physicochemical properties, includes efficient metal biosorption, soil fertility enhancement, and carbon sequestration. Consequently, there has been an increase in research for producing and exploiting biochar and hydrochar from algae. Both micro- and macro-algal biomass have strong potential due to their sustainability footprint and distinct properties. This review focuses on a comprehensive account of the synthesis of algal biochar and hydrochar and use in wastewater treatment to develop innovative solutions for efficient mitigation of several aqueous pollutants and heavy metal ions. The review discusses the various thermochemical production routes, biophysical characterization techniques, and modes of mechanism for wastewater bioremediation. Algal-based biochar and hydrochar are reported to have higher porosity and more diverse functional groups such as amines, hydroxyl, and carboxyl compared to their cellulosic and waste-derived counterparts, demonstrating an increased wastewater remediation efficiency. In addition, presence of inorganic metal including sodium, potassium, magnesium, and phosphorus in algal chars facilitates the formation of mesopores and graphite structures, improving their cation exchange capacity. Moreover, algal chars may exhibit pH buffering capacity, which could help stabilize the pH during wastewater treatment processes. Notably, the low O/C content of algal hydrochars enhances the binding and removal of organic pollutants including toxic dyes and antibiotics. The review highlights the development of modified algal chars to enhance the porosity, surface area, structural integrity, and adsorption capacity enabling a higher bioremediation potential. [ABSTRACT FROM AUTHOR]

[Display omitted] • CWs filled with combined organic media were developed for effective AMD treatment. • Abiotic and biotic treatment performances declined with decreasing pH. • High acidity (pH 2.0) caused failure of multiple pathways for AMD treatment. • Growth of functional microbes for AMD bioremediation was inhibited at low pH. • SRB and organic degrading bacteria were keystone taxa for AMD treatment. The impact of influent pH value (2.0–5.0) on remediation performance of constructed wetlands (CWs) packed with composite organic solids consisting of walnut shells, biochar and plastic filters for acid mine drainage (AMD) was evaluated in this study. Reed straw broth was supplemented to drive the microbial remediation process. Influent pH had a notable impact on both abiotic and biotic remediation performance, with very low efficacy at pH 2.0 and the best performance achieved at pH 5.0. The adsorption capacity of CW substrates for heavy metals and the growth of functional microbes for AMD treatment were restrained at high acidity. Moreover, the removal of conventional pollutants, plant growth and metal deposition in the CWs were negatively impacted by the dosing of AMD with low pH. A low pH of 2.0 resulted in a distinctive microbial community in the CWs with almost no sulfate-reducing bacteria (SRB). In other CW systems, SRB (Desulfosporosinus and Desulfobulbus) and organic degrading bacteria (Cellulomonas and Geobacter) were identified as keystone taxa to carry out AMD bioremediation synergistically in phase Ⅱ. CWs filled with composite organic substrates are promising systems for AMD treatment, but the pH of AMD should be preneutralized to ≥ 3. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nitrogen-rich pyrolysis effectively converts biomass into value-added products. • Theoretical computational modeling confirms the biomass three-component interactions. • Quantifying bio-oil component conversion to nitrogen-containing compounds (NCCs). • Unveils NCCs generation paths via intermediate chemical structures evolution analysis. • Machine learning is proven to be effective in handling interacting component systems. To optimize the targeted production efficiency of high-value nitrogen-containing compounds (NCCs: pyrrole, pyridine, nitriles, amides), this study extensively analyzed the interactions among cellulose, hemicellulose, and lignin under K and Ca presence during nitrogen-rich pyrolysis. By establishing a theoretical model, it confirmed how the three components interact during the pyrolysis process. The highest yield of biochar was observed with Ca. The proportion of NCCs in bio-oil increased by 4.45% with the addition of Ca and decreased by 1.81% with K. GC–MS characterization compared the evolution of intermediate chemical structures during the reaction with the formation of final products, specifically tracing NCCs generation pathways in bio-oil. First-time definition of bio-oil component conversion rates during nitrogen-rich pyrolysis. Aldehydes, ketones (with minimum conversion rates of 92.62% and 71.37%, respectively), and furans were identified as the most easily converted components into NCCs. Correlation analysis of bio-oil components supported this finding. Possible reaction pathways for NCCs generation during nitrogen-rich pyrolysis of ternary mixtures under mixed Ca or K addition conditions were identified. Additionally, the introduced machine learning model exhibited a high R2 value of 0.95 in predicting the product yields of ternary mixtures nitrogen-rich pyrolysis. This validates its effectiveness in handling interacting component systems. These results reveal interaction mechanisms among biomass three components in nitrogen-rich pyrolysis under K and Ca presence, offering new insights for optimizing NCCs production. [ABSTRACT FROM AUTHOR]

[Display omitted] • Antibiotics and antibiotic resistance genes (ARGs) are ubiquitous in the aquatic environment. • BC-catalyzed peroxides demonstrate high efficacy in the removal of antibiotics and ARGs. • BC-based catalytic removal mechanisms are systematically summarized. • The challenges of BC-catalyzed peroxides technology facing currently are discussed. • Future recommendations are suggested for scaling-up the use of BC-based catalyst. The increasing contamination of water bodies with antibiotics, along with the emergence of antibiotic resistance genes (ARGs), poses a significant threat to both ecological systems and human well-being. Hence, the adoption of advanced materials for water treatment has become imperative. Biochar (BC), a carbon-rich material derived from biomass, possesses a large surface area, porosity, and functional groups. These attributes render it a promising candidate for use as a catalyst or catalytic support in the elimination of these emerging pollutants. This review explores the capacity of waste biomass-derived BC in catalyzing peroxides for the removal of antibiotics and ARGs. It includes a meticulous analysis of various biomass sources suitable for BC production, examines the influence of pyrolysis conditions on BC's properties, summarizes the removal efficacy of BC-activated peroxides on antibiotics and ARGs, and reviews different modification techniques that improve its catalytic performance. Furthermore, the review delves into the underlying mechanisms that facilitate the catalytic removal of antibiotics and ARGs. Moreover, this review seeks to connect experimental research with industrial implementation by pinpointing the key challenges that need to be addressed. It examines the advantages of using BC for this purpose, in addition to addressing its limitations, such as potential secondary pollution from BC-based catalysts. The applicability of BC-based catalysts in real-world water treatment systems, as well as their economic viability, is also discussed. Finally, the review proposes future research directions to foster the development of sustainable BC-based catalytic technologies for water treatment. By addressing these key issues, this review offers valuable insights for translating the potential of BC into practical and effective use for treating antibiotic/ARG-contaminated water. [ABSTRACT FROM AUTHOR]

Lanthanum (La)-modified biochar has been widely investigated as a phosphate adsorbent material. However, its effectiveness and mechanism as an amendment material to manage sediment internal phosphorus (P) release under anoxic conditions is still unclear. Thus, a lanthanum carbonate-modified shrimp shell biochar (LBC-1) was synthesized for controlling sediment P release, and the efficacy, mechanism, and sediment microbial community impact of LBC-1 under two application modes (addition and capping) were investigated. The maximum adsorption capacity of LBC-1 for phosphate was 79.5 mg/g, superior to most La-modified biochar materials. The generation of LaPO 4 and Ca 5 (PO 4) 3 (OH) precipitates and the formation of inner-sphere complexes were the main adsorption mechanisms of LBC-1 for phosphate. Both the LBC-1 addition and capping treatments successfully blocked sediment P release under anoxic conditions, with the removal efficiencies of DGT-labile P in the overlying water being 97.7–99.7% and 97.5–99.5%, respectively. The conversion of the mobile P forms to the stable HCl-P form in sediments played an important role in the interception of internal P release by the LBC-1 addition treatment. Furthermore, the LBC-1 addition treatment also prevented internal P release by effectively adsorbing DGT-labile P in the interstitial water due to the excellent P adsorption capacity of LBC-1. However, the prevention of P release from sediments by the LBC-1 capping treatment was mainly attributed to the efficient adsorption of DGT-labile P by LBC-1 at the sediment/overlying water interface. The release of P driven by sulfate-reducing bacteria (SRB) was a key mechanism for the migration of P from sediment to interstitial water. The LBC-1 addition treatment reduced the relative abundance of SRB in the surface sediment and might inhibit the release of sediment P into the interstitial water, whereas the LBC-1 capping treatment had little effect on the relative abundance of SRB. In practice, the LBC-1 capping was easier to manipulate than the LBC-1 addition. These findings confirmed that sediment remediation using the LBC-1 capping treatment has great potential to manage internal P loading in eutrophic water bodies. [Display omitted] • LBC-1 addition/capping prevented P release from sediments under anoxic conditions. • LBC-1 addition blocking P release by inactivation of mobile P and adsorption of P. • LBC-1 capping prevented P release due to its high adsorption capacity to P. • LBC-1 addition/capping did not affect the diversity of microbial communities. [ABSTRACT FROM AUTHOR]

Prosopis juliflora (PJ) poses a significant concern to environmental engineers because of its adverse effects on the local communities and environment. The pyrolysis method was employed to recover value-added products from PJ biomass, producing biochar, bio-oil, and pyrogas. A 1:4 biochar-to-KOH ratio produced activated carbon (PJBAC-K4) with a specific surface area of 1140 m2/g and 80% mesopores. The electrode demonstrates a specific capacitance of 288 F/g at 1 A/g. Additionally, the results demonstrate a prolonged lifespan (at least 10,000 charge-discharge cycles), with a retention rate of 91.3% of the initial capacitance. Techno-economic analysis revealed that the net unit production cost of PJBAC-K4 is $18.41 per kg, which comes to around 0.006 cents/F, and the expected payback time is 5.16 years. Sensitivity analysis revealed that process economics is highly vulnerable to utility and raw material prices. The completed life cycle study revealed the environmental benefits of lower global warming potential compared to commercially available activated carbons. [Display omitted] • Prosopis julifora (PJ) was used for producing biochar, bio-oil, and pyrogas. • A 1:4 biochar-to-KOH ratio produced AC with a high specific surface area and mesoporosity. • The produced AC has a specific capacitance of 288F/g and good cyclic stability. • Technoeconomic analysis revealed that activated carbon production cost is around 0.006 cents/F. • Life cycle analysis showed the environmental benefits compared to commercial activated carbons. [ABSTRACT FROM AUTHOR]

Triclocarban (TCC), an antibacterial agent commonly used in personal care products, is one of the top ten contaminants of emerging concern in various environmental media, including soil and contaminated water in vadose zone. This study aimed to investigate TCC-contaminated water remediation using biochar-immobilized bacterial cells. Pseudomonas fluorescens strain MC46 (MC46), an efficient TCC-degrading isolate, was chosen, whereas agro-industrial carbonized waste as biochar was directly used as a sustainable cell immobilization carrier. According to the long-term TCC removal performance results (160 d), the biochar-immobilized cells consistently exhibited high TCC removal efficiencies (84–97%), whereas the free MC46 removed TCC for 76–94%. At 100 days, the detachment of the MC46 cells from the immobilized cell column was observed. The micro-Fourier-transform infrared spectroscopy results indicated that extracellular polymeric substance (EPS) was produced, but polysaccharide and protein fractions were washed out of the column. The lipid fraction of EPS adhered to the biochar, promoting TCC sorption for long-term treatment. The shortening of MC46 cells improved the tolerance of TCC toxicity. The TCC-contaminated water was successfully detoxified by the biochar-immobilized MC46 cells. Overall, the waste-derived biochar-immobilized cell system proposed in this study for the removal of emerging contaminants, including TCC, is efficient, economical, and aligned with the sustainable development concept of value-added utilization of waste. [Display omitted] • Long-term triclocarban (TCC) removal by the biochar-immobilized cells was 84–97%. • TCC degradation by free Pseudomonas fluorescens strain MC46 (MC46) was 76–94%. • MC46 produced extracellular polymeric substance (EPS) and promoted TCC adsorption. • Lipid from EPS coated on biochar, while polysaccharide and protein washed out. • Cell shrinkage enhanced TCC resistance, leading to the water detoxification. [ABSTRACT FROM AUTHOR]

Microplastics have attracted extensive public attention due to their harmful effects on environments and organisms, especially for small-size microplastics. Herein, six kinds of biochar were produced by wheat straw and cow dung at 500, 600 and 700 °C respectively for the removal of 1 μm polystyrene microplastics from soils. The removal efficiencies of microplastics exceeded 86% for all biochars. With increasing pyrolysis temperature, the removal performance of wheat straw biochars for microplastics gradually improved, while the removal efficiency of cow dung biochars decreased. Biochars effectively trapped microplastics within their channels, oxygen-containing functional groups (CO 3 2− and COO−) on the surface of biochars facilitated the adsorption of microplastics. After seven cycles of biochars recycling, the removal performance of microplastics remained above 85%, the removal process was primarily governed by the adsorption sites rather than the porous structure of biochars. This article provided eco-friendly and recyclable biochar materials for microplastics removal and technical support for addressing soil microplastics pollution. [Display omitted] • The highest removal efficiency of MPs by cow dung biochar reaches 92.4% at pH 9. • The removal efficiency of MPs remains above 85% after 7 cycles of biochar recycling. • Biochars show great stability and hold promising practical prospects for MPs removal. [ABSTRACT FROM AUTHOR]

Mixing feedstocks of varied aromatic/aliphatic content is a simple method for tailoring pore structures of activated carbon (AC) in activation. Herein, willow wood and homogenous biochar produced at 300 or 500°C, which have distinct content of aliphatic component, were co-activated with K 2 C 2 O 4 , at 800°C for changing pore characteristics of resulting AC. The results indicated that co-activation of willow and biochar diminished production of AC and impacted evolution of organics and gases through intensive volatiles-char interactions. The AC from the co-activation of willow with either biochar-300 or biochar-500 exhibited higher specific surface area than that from direct activation of willow (1409.7 or 1297.0 m2 g−1 versus 1243.6 m2 g−1), which was also higher than calculated average of that from feedstock (ca. 1160 m2 g−1). This resulted from intensified gasification of the biochar with H 2 O/CO 2 derived from willow, creating additional macropores and micropores of enlarged pore sizes. The enhanced gasification also reduced crystallinity of graphitic carbon, lowered O content via accelerated deoxygenation and diminished C O on nascent AC. Volatiles-char interactions also minimized pore filling from carbonaceous deposit generated from secondary condensation of primary volatiles. Additionally, direct activation of aliphatic-rich willow tended to form more micropores, while more mesopores were formed from aromatic-rich biochar. [Display omitted] • Activating aromatic-rich biochar forms more mesopores while more micropores from aliphatic willow. • Activating mixed biochar/willow reduces yields of activated carbon (AC) but enhances pore development. • Intensified gasification of biochar with H 2 O/CO 2 from willow creates additional pores. • Enhanced gasification in co-activation makes AC carbon-rich but with lower crystallinity. • Volatile-char interaction diminishes pore filling from the secondary condensation of volatiles. [ABSTRACT FROM AUTHOR]

This study focuses on the use of a molten salt reaction medium (NaCl-KCl-LiCl) in the lignin pyrolysis process to modify the pyrolysis volatiles and biochar structure. The effect of pyrolysis reaction temperature (300°C, 400°C, 500°C, and 600°C) and lignin/molten salt mass ratios (3:1, 1:1, 1:3 and 1:5) on the evolution behavior of volatiles and biochar structure was explored. The pyrolysis products were determined using GS-MS, CO 2 adsorption-desorption analyses, SEM, elemental analysis, proximate analysis, Raman, XRD, and TG/DTG analysis. Results indicated that the introduction of molten salt can enhance the lignin depolymerization, leading to the production of phenolic precursors. Moreover, the metal cation (Na+, K+ and Li+) of molten salt can in-situ induce the modification of biochar structure with high porosity. The lower sulfur content in biochar was attributed to the immobilize function of molten salt. The evolution behaviour of volatiles and biochar structure during molten salt-assisted lignin pyrolysis was proposed. This study can serve as a benchmark for the high-value recycling of industrial lignin waste. [Display omitted] • Lignin pyrolysis assisted by ternary chloride salts was systematically investigated. • Ternary chloride salts can enhance the depolymerization of lignin waste. • The porosity of biochar was enhanced through the in-situ induced with molten salt. • The mechanism of promoting deep pyrolysis of lignin by molten salt was investigated. [ABSTRACT FROM AUTHOR]

During the biomass pyrolysis polycyclic aromatic hydrocarbons (PAHs), a type of toxic-organic pollutants is formed, and remains the production of biochar. Short comings of the biochar manufacturing plants and condensation effect of pyrolysis vapors in cold regions during the pyrolysis have a noticeable effect. Chemical compositions and structural differences between the feedstock influence development and distribution of PAHs while pyrolysis procedure or feedstock contaminated with PAHs from sources may contain higher levels of these compounds. Even though previous efforts reviewed on the toxicity, occurrence, and growth mechanisms of PAHs in biochar, the interaction effect of the pyrolysis process parameters has not been systematically reviewed. In this regard, optimizing the combined effect of the pyrolysis process parameters towards PAH content in biochar is crucial. Because of this, the present study focuses on current research gaps, optimizing pyrolysis process conditions for enhancing the performance of biochar, while reducing the toxic effects of biochar, and revealing the individual and interactive effects of pyrolytic process parameters. A statistical analysis of the previous results has been carried out and desirability contour diagrams for PAHs have been generated to pinpoint the extent of interactive effects of different pyrolysis process parameters. This review focuses to pathways for optimizing the pyrolysis process parameters during biochar production to ensure cleanliness and safety. Monitoring and controlling the pyrolysis process to obtain the preparation of high-class biochar following an international biochar production guideline is important. [Display omitted] • Feedstock, pyrolysis parameters, reactor type, and configuration.dictates the PAH in biochar • Interactive effects and vapors condensation in cooler regions have a greater implication. • Optimizing the pyrolysis parameters and following biochar production protocols is necessary. [ABSTRACT FROM AUTHOR]

Rosemary waste was used as a precursor to produce biochar by slow pyrolysis, examining the influence of feedstock type (leaves or stems) and pyrolysis temperature on biochar properties. The structural, thermal, morphological and physicochemical characteristics of the original feedstocks and biochars were analyzed by XRD, FTIR, SEM, DTA/TGA and EA (CHNSO). The study revealed differences in the chemical composition of rosemary leaves and stems. Leaves showed higher levels of hemicellulose and extractive, while stems contained more cellulose and lignin. Biochar yields from stems are higher than those from leaves, and both decrease as pyrolysis temperature rises from 400 to 900°C. The density increases with increasing pyrolysis temperature, that of leaf biochars is greater. Stem biochars had a higher surface electronegativity than leaf biochars. Two pyrolysis temperature ranges have been determined. At T < 700°C, most of the hydrolyzable functional groups in the feedstock were retained in the biochars. Leaf biochar leachates have very high electrical conductivities compared to stem biochars and feedstocks, indicating significant salt content. At T ≥ 700°C, stem biochars have greater chemical stability to oxidation (average = 106.9 %) than leaf biochars (average = 100.6 %). Stems biochars, prepared at T <700°C, can be better valorized in carbon storage as a long-term C sink or replaces fossil carbon in industrial manufacturing, it can also be better valorized in the agricultural sector. [Display omitted] • Biochar from rosemary waste provides a sustainable way to manage agricultural by-products and reduce environmental impact. • Effect of rosemary waste components on biochar yield and physico-chemical characteristics is assessed. • Effect of pyrolysis temperature on volatilization, decomposition, pore structure, and surface area of biochar is analyzed. • Biochar, a carbon-rich material, offers diverse applications in pollutant removal, soil improvement, and carbon storage. [ABSTRACT FROM AUTHOR]

As people's living standards gradually improved, the demand for fruits increases every year. At the same time, the fruit waste yield also increases, resulting in environmental pollution pressure. Currently, how to dispose the waste is highly concerned to scientists. Producing biochar by thermal conversion is a promising method for the disposal and the valorization of fruit waste. The biochar can be used in various fields, including electrode materials for capacitors, catalyst carriers for electrocatalysis, anaerobic fermentation media for microorganisms, soil improvement, and biosensing carbon dots. Fruit waste, as a typical biomass, primarily consists of proteins, fats, starch, sugars, and cellulose. Compared to other biomasses, for examples, straw and wood residues, fruit waste has a higher moisture content , resulting in different methods used to produce biochar. Currently, pyrolysis, hydrothermal carbonization, and physical chemical activation have been studied on biochar production. However, the industrialization of biochar production from fruit waste is still limited due to the lack of relevant research supports, such as understanding the comprehensive and extensive evaluations. This study provides a comprehensive review of the current methods for preparing biochar from fruit waste, examining the impacts of temperature, residence time, and raw materials. Additionally, it outlines optimal preparation methods and application scenarios for fruit biochar by comparing with straw biochar, offering both experimental and theoretical insights to highlight the valuable fruit biochar. [Display omitted] • The preparation, activation, and application of fruit biochar are reviewed. • Components for the synthesis of fruit biochar are systematically discussed. • Advanced strategies for the electrochemical performance of biochar are manifested. • The challenges remaining are discussed and future research directions are proposed. [ABSTRACT FROM AUTHOR]

Microwave-assisted catalytic pyrolysis (MACP) of solid digestate (SD) into value-added products presents a promising solution for waste SD. Both types of catalysts and reactor temperature critically influence the properties of MACP products. This study systematically investigated pyrolysis of SD mixed with different catalysts (K 3 PO 4 , natural zeolite, and mixture of K 3 PO 4 and natural zeolite) at various pyrolysis temperatures (300, 400, and 500 ℃) for bio-oil and biochar production. The results showed that higher temperatures led to reduced bio-oil and biochar yields, favoring gas production. The bio-oil derived from SD with 20 wt% K 3 PO 4 and 20 wt% natural zeolite at 500 ℃ exhibited the largest fraction of aromatic hydrocarbons, reaching 92.43 % and 91.56 %, respectively. Catalytic pyroysis resulted in reduction in bio-oil acidity. Biochar specific surface area is influenced by both heating rate and temperature, with the highest surface area (207 m2/g), pore volume (0.2244 cm³/g), and a more regular pore structure being obtained at 500 ℃ and 66.1 °C/min with 20 wt% K 3 PO 4. This work demonstrated the feasibility of upgrading waste SD into value-added chemicals, materials, and energy-rich fuels by MACP. Notably, SD with 20 wt% K 3 PO 4 at 500 ℃ represents the optimal operating condition for both bio-oil and biochar production. [Display omitted] • Catalytic pyrolysis resulted in a reduction in bio-oil acidity. • K 3 PO 4 catalytic pyrolysis yielded more aromatic hydrocarbons in bio-oil. • Biochar specific surface area is influenced by both heating rate and temperature. • Highest surface area (207 m2/g) was obtained at 500 ℃ with 20 wt% K 3 PO 4. [ABSTRACT FROM AUTHOR]

Biochar is rapidly gaining traction as a commercially viable carbon dioxide removal (CDR) technology that can be applied globally at various scales. However, the vast majority of published research studies have involved laboratory experiments conducted in an inert environment under well-controlled conditions of heating rate, maximum temperature and residence time. To expand the biochar industry within the next decade as a CDR platform, there is a need to understand differences between biochar produced under "ideal" laboratory conditions versus those generated using the same feedstocks in continuous, industrial scale systems. In the present work, biochar was produced from widely available organic waste feedstocks, including mixed cafeteria food waste, blended coffee grounds and chaff, grape pomace and wood pellets, using both a laboratory furnace operated in a nitrogen environment, and a continuously operated commercial system capable of processing up to ∼1 t/day of dry feedstock. High quality biochar (H:C < 0.7) was obtained for all feedstocks converted by both systems, however high variability in volatiles and decomposition rates was observed in the thermogravimetric analysis (TGA) results for industrial scale biochar. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) showed similar morphologies and surface chemistries in both laboratory and industrial scale samples, in agreement with reported literature data. Based on this initial comparative assessment, we conclude that commercially available thermochemical systems have potential as localized organic waste valorization technologies to produce high quality biochar. We identified important control variables that have the greatest effect on the resulting biochar. Despite the reported differences between biochar materials derived from the same feedstock, key properties critical for soil amendment and remediation applications (i.e., H:C, surface area, %C org , etc.) are reasonably consistent between laboratory and continuously fed equipment typical of commercial-scale systems. Thus, biochar materials obtained from well-controlled laboratory experiments conducted in a pure nitrogen atmosphere can be reasonably representative of biochar produced from the same feedstocks using industrial scale equipment. [Display omitted] • Biochars from laboratory furnace and small industrial scale system were compared. • Both platforms produced quality biochar, adequate for soil amendment. • Industrial scale biochar had higher surface area but similar CDR potential. [ABSTRACT FROM AUTHOR]

Composite with a high specific surface area of 224.62 m2 g−1 was prepared by adding urea as a nitrogen source to hazelnut shell biochar (HSB). Nitrogen doping significantly enhanced the ability of biochar for Cr(VI) elimination, achieving twice the removal efficiency of unmodified biochar. The impacts of varying the pH and initial concentrations on Cr(VI) removal by urea-modified biochar (N-HSB) were investigated. The Cr(VI) removal by N-HSB was better described by intra particle diffusion model and pseudo-second order kinetic model under optimal conditions. Furthermore, XPS, FTIR, SEM, and BET analyses were used to verify the pivotal roles of oxygen- and nitrogen-containing functional groups. Electrostatic attraction, redox reaction, and complexation constituted the principal mechanisms facilitating Cr(VI) elimination by N-HSB. This study demonstrated that the modification of biochar with urea as a nitrogen source represented a promising strategy for enhancing the removal capacity of biochar for Cr(VI) in aqueous environments. [Display omitted] • Waste hazelnut shells were utilized as a biomass precursor to prepare biochar. • Nitrogen-doped biochar was prepared using economical and available urea as the nitrogen source. • Electrostatic attraction, reduction, and complexation were involved in Cr(VI) removal. • The use of urea significantly increased the capacity of biochar on Cr(VI) removal. [ABSTRACT FROM AUTHOR]

Biochar amendment has emerged as a potential solution for preventing, remediating, and mitigating agricultural compound pollution. This groundbreaking technique not only improves crucial soil properties like porosity, water retention capacity, cation exchange capacity, and pH, but also intricately impacts the interaction and retention mechanisms of polluting molecules. In this study, we investigate the dynamic of the herbicide Imazapic when subjected to applying pyrolyzed biochars, specifically at temperatures of 300 and 500 °C, within the context of a low-fertility soil characterized as dystrophic Yellow Ultisol (YUd) in a sugarcane cultivation area in Igarassu-PE, Brazil. The biochars were produced from sugarcane bagasse by pyrolysis process in a muffle furnace. In laboratory conditions, with saturated soil columns under steady-state, analyses of the mechanisms involved in interaction and transport and determining hydrodispersive parameters for Imazapic were performed by the two-site nonequilibrium transport model using the CXTFIT 2.0 program. Samples of YUd soil amended with biochar pyrolyzed at 300 °C presented a negligible interaction with Imazapic. However, adding biochar pyrolyzed at 500 °C (BC500) to the soil samples enhanced the adsorption coefficient and improved the interaction with Imazapic. This research points out that biochar produced from agricultural waste biomass, such as sugarcane bagasse specifically pyrolyzed at 500 °C, offers a potential means to adsorb herbicides, reducing their leaching to deeper layers of the amended soils and the risk of groundwater contamination and potential environmental negative impacts. • Sugarcane feedstock pyrolysis: an example of sustainable biochar production for controlling Imazapic leaching in amended soils. • Imazapic leaching and release in biochar-amended soil emphasize pyrolysis temperature's influence. • Biochar produced at 500 °C improves Imazapic leaching control in amended soils. [ABSTRACT FROM AUTHOR]

Biochar amendment can improve soil phosphorus (P) availability, yet the influence of microbial community structure, especially certain keystone taxa on P dynamics remains uncertain. A pot experiment was conducted on a highly weathered Ferralsol to investigate how the amendment with biochar and P-fertilizer (CK, no biochar and P addition; PP, 30 kg P ha−1 addition; BC, 4 % biochar addition and BP, 30 kg P ha−1 combined with 4 % biochar addition) affect soybean (Glycine max (L.) cv. Huaxia-9) P uptake, soil P dynamics and its association with bacterial community structure and keystone taxa. The biochar-amended treatments (BC and BP) led to a 50–130 % increase in P uptake and a ten-fold rise in labile P proportion compared to treatments without biochar (CK and PP). This could be associated with the incorporation of P from biochar, as well as the altered soil P availability by elevated soil pH, soil organic carbon (SOC), microbial biomass P and alkaline phosphatase activity. Furthermore, biochar amendments altered bacterial community composition by increasing the relative abundance of Gemmatimonadetes, Bacteroidetes and Verrucomicrobia phylum by over three-fold, while decreasing the relative abundance of Chloroflexi and Acidobacteria phylum by over 50 %, compared to the non-biochar treatments. Additionally, the elevated C:P ratio following biochar amendment played a dominant role in shaping the keystone taxa, which was identified as the primarily microbial predictor of soil labile P. Specifically, biochar amendment increased microbial network complexity, inducing a shift in keystone taxa from oligotrophs to copiotrophs, such as Rhizobiales, Sphingomonadales and Rhodospirillales, which are wildly recognized for their roles in soil P mobilization. Taken together, our findings suggested that biochar-induced shift in keystone taxa is one of the major predictors of soil P dynamics, highlighting the potential of harnessing specific keystone taxa for improving soil P availability. • The elevated pH, SOC, MBP and phosphatase by biochar affected soil P dynamics. • Biochar amendment increased microbial network complexity and organization. • Biochar amendments shifted keystone taxa from oligotrophs to copiotrophs. • The shift in putative keystone taxa was the primarily predictor of soil labile P. [ABSTRACT FROM AUTHOR]